Switchably controlled liquid sealed type vibration isolator

ABSTRACT

A switched vibration isolator has an elastic base member fixed to a first fitting member, and a tubular member fixed the elastic base member. A partition device is disposed in the tubular member, and has an outer diameter, a first partition side opposing the elastic base member defining a main liquid chamber therebetween, and a second partition side opposite the first partition side. The partition device defines an orifice communicating with the main liquid chamber. A partition receiving plate has a diameter greater than an outer diameter of the partition device and the partition device is mounted thereon. A diaphragm is disposed opposing the partition receiving plate and defining an auxiliary liquid chamber communicated with the main liquid chamber via the orifice. The partition receiving plate and the diaphragm are fixed in place together by an end of the tubular member.

This is a Continuation, of application Ser. No. 09/617,870 filed Jul.17, 2000, now U.S. Pat. No. 6,425,575.

BACKGROUND OF THE INVENTION

This invention relates to a switchably controlled liquid sealed typevibration isolator used to support a power unit, such as an automobileengine in a vibration isolating manner.

A switchably controlled liquid sealed type vibration isolator adapted toswitch vibration isolating characteristics thereof in accordance withtwo kinds of vibrations in different frequency regions, such as shakingvibration and idling vibration, has been proposed as a liquid sealedtype vibration isolator for use as a mount for supporting a vibratingbody, such as an automobile engine, etc. so as not to have the vibrationof the vibrating body transmitted to a body of a vehicle.

For example, Japanese Patent Laid-Open No. 173372/1999 proposes aswitchably controlled liquid sealed type vibration isolator including ametal fixing member on a side of a vibration source, an outercylindrical metal member on a side of a support, a vibration isolatingbase member interposed between the two metal members and formed of anelastic rubber member, a first diaphragm fixed to the outer cylindricalmetal member so as to be opposed to the vibration isolating base member,and a partition provided between the diaphragm and vibration isolatingbase member, the partition and vibration isolating base member defininga main liquid chamber therebetween, the partition and first diaphragmforming therebetween a first auxiliary liquid chamber communicating withthe main liquid chamber via a first orifice, the partition beingprovided at a main liquid chamber-side portion thereof with a secondauxiliary liquid chamber communicating with the main liquid chamber viaa second orifice, and an atmospheric pressure and negative pressurechangeover chamber separated from the second auxiliary chamber via asecond diaphragm.

In this proposed liquid sealed type vibration isolator, the partition isformed of a main partition member defining the first orifice on an outercircumference thereof, and a partition plate member defining the secondauxiliary chamber and orifice. The main partition member, to which thesecond diaphragm is fixed, forms the change-over chamber on the mainliquid chamber-side portion and is fitted in an inner circumference ofthe outer cylindrical metal member. The partition plate member is fittedaround the diaphragm to hold a circumferential edge portion thereof.Both the main partition member and partition plate member are installedheld between a main liquid chamber-side surface of the vibrationisolating base member and a liquid chamber-side stepped portion of theouter cylindrical metal member.

However, in the above-mentioned construction, the main partition memberand partition plate member have to be installed submerged in a liquid inorder by a press fitting method as orifice-communicating openings ofboth thereof are positioned. Therefore, the structure to be assembled iscomplicated, and, moreover, a high stability of the structure is rarelyobtained due to variations in accuracy of other parts.

The main partition member and partition plate member are held betweenthe vibration isolating base member and the liquid chamber-side steppedportion of the outer cylindrical metal member and thereby retained in amere contacting state. Therefore, the predetermined functions becomeunable to be fulfilled due to changes with the lapse of time in thecondition of the parts during the use of the vibration isolator in avehicle-mounted state. Such changes are ascribed to the fluctuation of aliquid pressure caused by the vibration of the vibration isolating basemember, or permanent set in fatigue and slip of the rubber portionsbetween the parts caused by the heat. The changes thus cause the sealingto become insufficient, and the passages working as the orifices to beshort-circuited.

The present invention has been made in view of these facts, and providesa switchably controlled liquid sealed type vibration isolator having astructure which permits an inner partition, by which an inner hollowspace is divided into a main liquid chamber and two auxiliary liquidchambers, to be assembled tentatively in an air environment, pluralconstituent parts to be combined together reliably and easily withoutbeing dislocated, and, moreover, the relative displacement of theconstituent parts which occurs due to changes with the lapse of time ofthemselves in a vehicle-mounted state to be reduced to a low level,whereby retention of an excellent sealed condition among the parts andthe improvement of the durability of the same parts are attained.

SUMMARY OF THE INVENTION

The present invention provides a switchably controlled liquid sealedtype vibration isolator including a vibration isolating base memberformed of an elastic rubber member, a first metal fixing member combinedwith one of upper and lower portions of the vibration isolating basemember, a main cylindrical metal member combined with the other portionof the vibration isolating base member, a first diaphragm fixed to themain metal member so as to be opposed to the vibration isolating basemember, a partition provided between the vibration isolating base memberand first diaphragm, a main liquid chamber formed between the partitionand vibration isolating base member, a first auxiliary liquid chamberformed between the partition and first diaphragm, a second auxiliaryliquid chamber formed on a main liquid chamber-side portion of thepartition, a change-over chamber separated from the second auxiliarychamber via a second diaphragm and capable of receiving therein anatmospheric pressure and a negative pressure in a switchable manner, andfirst and second orifices communicating the main liquid chamber with thefirst and second auxiliary chambers respectively, the vibration isolatorfurther having the following structure so as to solve the aforementionedproblems.

The partition has at an outer circumferential portion thereof a mainpartition member forming the first orifice, and the second diaphragm isprovided on a main liquid chamber side portion of the main partitionmember so as to form the change-over chamber in a diametrically innerportion thereof. A partition plate member pressing a circumferentialportion of the second diaphragm toward the main partition member to formthe second auxiliary liquid chamber between the partition plate memberand the same diaphragm is engaged with and fitted firmly around an outercircumferential portion of the main partition member by a swaging devicefor this outer circumferential portion. A portion defined by the mainpartition member and partition plate member on an outer side of thesecond auxiliary liquid chamber is formed as the second orifice. Apartition receiving plate having an outer circumferential edge portionextending outward beyond an outer end of the main partition member isfixed by a press fitting device with respect to the main partitionmember to the portion of the main partition member which is on the sideof the first auxiliary liquid chamber. The partition plate member isfitted liquid-tightly in an inner circumferential portion of the mainmetal member, and the outer circumferential edge portion of thepartition receiving plate is fixed with the first diaphragm to the mainmetal member by a swaging member.

According to the liquid-sealed type vibration isolator of-thisconstruction, the structural parts of the partition incorporated in aninner portion thereof, i.e. the main partition member on an outercircumferential side of which the first orifice is formed, the seconddiaphragm forming the change-over chamber on the portion thereof whichis on the side of the main liquid chamber, the partition plate memberforming the second auxiliary chamber and orifice, and parts of thepartition receiving plate can be combined together in the air initiallywith ease and separately from the main metal member without causingthese members and parts to be dislocated. Therefore, after such atemporary combining operation, plural structural parts can be combinedaccurately by press fitting the partition plate member of the partitionfirmly into an inner circumference of the main metal member, and thenswaging the outer circumferential portion of the partition receivingplate with the first diaphragm to the main metal member, whereby aliquid sealed type vibration isolator provided with two auxiliary liquidchambers, two orifices and two diaphragms can be assembled easily.

Especially, since the partition plate member pressing the seconddiaphragm to form the second auxiliary liquid chamber and orifice isfitted firmly in an engaged state around the outer circumference of themain partition member by a swaging device for the same outercircumference, the main partition member and the main partition platemember are combined with each other without a fear of their beingseparated from each other. This enables the second diaphragm to bepressed reliably, and can prevent an excessive decrease in thesealability of the parts and the short-circuiting of the passage as anorifice which are ascribed to changes with the lapse of time in thevibration isolating base member during the use thereof.

In this liquid sealed type vibration isolator, a second metal fixingmember covering a space on the outer side of the first diaphragm isprovided, which is swaged with the partition receiving plate and firstdiaphragm to the main metal member, and these parts can also be combinedtogether easily just as the above-mentioned parts.

In the liquid sealed type vibration isolators of each of theabove-described inventions, the main partition member is provided on theportion of an outer circumference thereof which is on the side of thefirst auxiliary liquid chamber with an orifice-forming recess, which aredefined by the partition receiving plate and main metal member to formthe first orifice. Therefore, the main partition member can bemanufactured easily, and is suitable for practicing the vibrationisolator.

The partition plate member is preferably formed by fitting firmly theouter circumferential portion thereof around the outer circumference ofthe portion of the main partition member which is on the side of themain liquid chamber, bending at least a part of a circumferential endportion of the partition plate member inward in the above-mentionedorifice-forming recess, and swaging this bent portion to the mainpartition member. This enables the partition plate member to be swagedby utilizing the orifice-forming recess.

The circumferential end portion of the partition plate member can beswaged at plural circumferentially spaced parts thereof to the mainpartition member, and also at substantially all parts of thecircumference thereof to the same member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view showing one embodiment of theswitchably controlled liquid sealed type vibration isolator according tothe present invention;

FIG. 2 is a perspective view showing constituent parts, which are in amutually separated state, of a partition in the same embodiment;

FIG. 3 is a sectional view of the constituent parts of FIG. 2 in aseparated state;

FIG. 4 is a sectional view of the constituent parts of FIG. 2 in aninitially assembled state; and

FIG. 5 is a sectional view of a partition in another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the switchably controlled liquid sealed typevibration isolator according to the present invention will now bedescribed with reference to the drawings but the present invention isnot limited to these embodiments.

Referring to FIGS. 1-4, a liquid sealed type vibration isolator A has avibration isolating base member 2, formed of an elastic rubber memberwhich receives a load of a power unit, such as an engine, etc. Thevibration isolating base member 2 is joined to an upper opened side of acylindrical main metal member 1, and a first metal fixing member 3. Thatis, the main metal member 1 is joined to the first metal fixing member 3via the vibration isolating base member 2. In the illustrated vibrationisolator A, the vibration isolating base member 2 is formed in asubstantially trapezoid-conical shape, and fixed air-tightly at an uppersmaller-diameter end portion and a lower larger-diameter outercircumferential portion to the first metal fixing member 3 and theopened portion of the main metal member 1 respectively by avulcanization bonding device.

A first diaphragm 4, opposed to the vibration isolating base member 2and formed of a rubber film, and a second metal fixing member 5,covering a an outer side of the first diaphragm 4, are fixed in a sealedstate at a lower opened side of the main metal member 1 by a swagingdevice to be described later. A reference numeral 41 denotes an annularreinforcing member vulcanization bonded to the diaphragm 4.

The first metal fixing member 3 is substantially disc-shaped, and afixing bolt 31 fixed to a central portion of the first metal fixingmember by a press fitting device or a welding device projects upwardtherefrom, by which fixing bolt 31 the first metal fixing member 3 issecured to a power unit of an automobile.

The second metal fixing member 5 has a substantially cylindrical shapebottom wall portion 52, and a flange-like opened edge portion 51 thereofis swaged with a partition, which will be described later, to a lowerend portion 1 a of the main metal member 1. The bottom wall portion 52of the second metal fixing member 5 has a fixing bolt 53 fitted thereinby a press fitting device so that the fixing bolt 5 projects downwardtherefrom. The second metal fixing member 5 is secured to a vehiclebody-side member by the fixing bolt 53. A space between the second metalfixing member 5 and first diaphragm 4 is formed as an air chamber 6.This air chamber is communicated with the atmosphere in some cases, andformed as an air-tight chamber in some cases.

A partition 10 is air-tightly fitted in an inner circumference of aportion of the main metal member 1 which is between the vibrationisolating base member 2 and first diaphragm 4, via a seal rubber layer 2a integral with the vibration isolating base member 2. An incompressibleliquid, such as water or ethylene glycol is sealed in an inner chamberbetween the vibration isolating base member 2 and the first diaphragm 4.This inner chamber is divided by the partition 10 so as to form a spacebetween the vibration isolating base member 2 and partition 10 as a mainliquid chamber 7, and a space between the first diaphragm 4 andpartition 10 as a first auxiliary liquid chamber 8. The portion of thepartition 10 which is on the side of the main liquid chamber 7 isprovided therein with a second auxiliary liquid chamber 9, a change-overchamber 12 which is separated from the second auxiliary liquid chamber 9by a second diaphragm 11, and which permits an atmospheric pressure anda negative pressure to be introduced thereinto switchably, and first andsecond orifices 13, 14 which communicate the main liquid chamber 7 withthe first and second auxiliary liquid chambers 8, 9 respectively, andwhich have different liquid passage resistances. In the illustratedembodiment, the first auxiliary liquid chamber 8 communicates with thefirst orifice 13 having a higher liquid passage resistance (smallercross-sectional area), and the second auxiliary chamber 9 communicateswith the second orifice 14 having a lower liquid passage resistance(larger cross-sectional area).

As shown in FIGS. 1-4, the partition 10 includes a main partition member15, a partition plate member 16 and a partition receiving plate 17, andhas the following structure.

The main partition member 15 is made integral of a metal material, suchas aluminum, or a rigid material, such as a synthetic resin, and has anannular shape as shown in FIG. 2. The main partition member 15 isprovided in a portion of an outer circumference thereof, which is on theside of the first auxiliary liquid chamber 8, with an orifice-formingrecess 19 so that a portion 18 on the side of the main liquid chamber 7remains as a flange-shaped portion. The recess 19 is defined by thepartition receiving plate 17 and main metal member 1, whereby the recess19 is formed as the first orifice 13 which communicates the main liquidchamber 7 and the first auxiliary liquid chamber 8 with each other. Theflange-shaped portion 18 is provided with a recessed communicationsection 13 a which communicates the first orifice 13 and main liquidchamber 7 with each other.

An upper inner portion, which is on the side of the main liquid chamber7, of the main partition member 15 has a second diaphragm 11. An annularmetal collar 20 is fixed to an outer circumferential portion of of thesecond diaphragm 11 by a vulcanization bonding device. The seconddiaphragm 11 is fixed coaxially with the central axis by press fittingthe metal collar 20 into the main partition member 15. A clearancebetween the second diaphragm 11 and the main partition member 15 isformed as the change-over chamber 12 having a predetermined height. Areference numeral 12 a denotes a projection for maintaining theclearance of not smaller than a predetermined height.

In the illustrated embodiment, the central portion of an-upper surfacewhich corresponds to the change-over chamber 12 of the main partitionmember 15 is recessed curvilineally, and a groove 15 b for press fittingthe metal collar thereinto is formed around this recessed portion 15 a.The second diaphragm 11 is fixed to the main partition member so as tocover the recessed portion 15 a by press fitting the metal collar 20into the groove 15 b.

The change-over chamber 12 is joined to a change-over device (notshown), such as a valve, etc. which can be switchably connected toeither a negative pressure source or an atmospheric pressure source viaa communication passage 21 extending through an inner portion of themain partition member 15 and communicating at a side surface of the mainmetal member 1 with an outer portion thereof. Thus, either a negativepressure or an atmospheric pressure can be introduced into thechange-over chamber 12 by operating the change-over device in accordancewith an instruction signal, etc. from a control unit.

As a result of the above arrangement, the second diaphragm 11 can becontrolled in a switching manner to an operating condition and anon-operating condition. In order to work mainly the second orifice 14of a lower liquid passage resistance (larger cross-sectional area), thesecond diaphragm 11 is maintained in a movable condition. In order towork the first orifice 13 of a higher liquid passage resistance, themovement of the second diaphragm 11 is stopped so as not to operate thesecond orifice 14 of a larger cross-sectional area. Thus, a sufficientdamping effect can be displayed with respect to vibrations in differentfrequency regions, by the respective orifices 13, 14.

The partition plate member 16 is a pressure molded product formed mainlyof a steel plate, and has an annular projection 16 a on a lower surfacethereof. The partition plate member 16 is fitted firmly in the mainliquid chamber 7 and engaged with the main partition member 15, asdescribed below, by a swaging device to engage the outer circumferenceof the main partition member 15 so as to seal the circumferential edgeportion 11 a of the second diaphragm 11 against the projection 16 a.Thus, a space between the partition plate member 16 and the diaphragm 11on an inner side of the projection 16 a is formed as the secondauxiliary liquid chamber 9. A space on an outer side of the secondauxiliary liquid chamber 9 and defined by the main partition member 15and partition plate member 16 forms the second orifice 14 communicatingthe main liquid chamber 7 and second auxiliary liquid chamber 9 witheach other via communication ports 23, 24 and has a comparatively largecross-sectional area. The first orifice 13 communicates with the mainliquid chamber 7 through the communication port 23 of the second orifice14. Namely, the first and second orifices 13, 14 have a common exit withrespect to the main liquid chamber 7.

The partition plate member 16 is engaged with and fitted firmly aroundthe main partition member 15 by swaging the outer circumferentialportion 26 of the partition plate member 16 into a cylindrical portionof such a diameter that permits a cylindrical bent portion thus formedto be press fitted in the inner circumference of the main metal member1, fitting firmly the outer circumferential portion 26 around the outercircumference of the flange-shaped portion 18 by swaging into theorifice-forming recess 19 at least a part of the circumferential endsection 26 a of the outer circumferential portion 26 to thereby swagethe circumferential end section 26 a to the flange-shaped portion 18.

The swaging of the circumferential end section 26 a is done preferablyat substantially all parts of the circumference thereof, i.e., over thewhole circumferential length of the recess 19 as shown in the drawingsbut the circumferential end section 26 a can also be swaged partially atplural portions thereof spaced from one another at predeterminedintervals to the main partition member 15. In this case, the portions tobe swaged can be formed like projecting claws which are swaged.

The outer circumferential portion 26 is provided with one or pluralcircumferentially spaced openings 22 for carrying out easily thereplacement of air with a liquid when the partition plate member 16 isincorporated into the main metal member 1. The openings 22 are closedwith a seal rubber layer 2 a when the outer circumferential portion 26of the partition plate member 16 is fitted firmly in the innercircumference of the main metal member 1.

The partition receiving plate 17 is a pressure molded product obtainedfrom a steel plate identical with the steel plate mentioned above,having an opening in the central portion thereof and formed of adoughnut-shaped disc of a diameter slightly larger than that of the mainpartition member 15. The partition receiving plate 17 is positioned on aportion of the main partition member 15 which is on the side of thefirst auxiliary liquid chamber 8 and an opened edge portion 28 in acentral section thereof is press fitted into the recess 25 provided in alower surface of the main partition member 15. Thus, the outercircumferential edge portion 27 is fixed firmly projecting outwardbeyond an outer edge of the main partition member 15. In this condition,a recess 13 b, continuing from the recess 19, is aligned with an opening17 a so that the first orifice 13 communicates with the first auxiliaryliquid chamber 8.

In this structure, the partition 10 is in a initially assembled state asshown in FIG. 4, in which the outer circumferential portion 26 of thepartition plate member 16 is press fitted liquid-tightly in the innercircumference of the main metal member 1 up to a position in which theouter circumferential portion 26 engages a circumferential edge portion2 b of the surface (lower surface in FIG. 1) on the side of the mainliquid chamber 7 of the vibration isolating base member 2. In addition,the outer circumferential edge portion 27 of the partition receivingplate 17, the first diaphragm 4 having the reinforcing member 41, andopened edge portion 51 of the second metal fixing member 5 are swagedtogether using the lower end portion 1 a of the main metal member 1.

In the case of the illustrated embodiment, a larger diameter portion ofthe vibration isolating base member 2 has, at a part of acircumferential section thereof, a projection 2 c reinforced with a partof the main metal member 1. A stabilizer 29, fixed to the first metalfixing member 3 with a common tightening member, is disposed so as toextend near upper and lower surfaces of the projection 2 c, and functionas a stopper for restricting excessive vertical displacement of theprojection 2 c.

In order to assemble the liquid sealed type vibration isolator Aconstructed as described above, the metal collar 20 is press fitted intothe press fitting groove 15 b first, in the recess 15 a in the uppersurface of the main partition member 15 while in air, whereby the seconddiaphragm 11 is fixed so as to form the change-over chamber 12 betweenthe second diaphragm 11 and main partition member 15. The partitionplate member 16 is press fitted in an engaged state at the outercircumferential portion 26 thereof around the outer circumference of theflange-shaped portion 18 of the main partition member 15, and swagedthereto by a swaging member provided at the circumferential end section26 a of the outer circumferential portion 26. Thus, the circumferentialedge portion of the second diaphragm 11 is pressed by the projection 16a of the partition plate member 16, and the second auxiliary liquidchamber 9 and second orifice 14 are formed. The partition receivingplate 17 is fixed firmly at the press fitting portion in the centralportion thereof to a lower side portion of the main partition member 15which is on the side of the first auxiliary liquid chamber 8, wherebythe partition 10 is tentatively assembled as shown in FIG. 4. Duringthis time, the parts can be positioned as the positions of theorifice-forming openings and communication ports are ascertainedvisually with ease, and the tentative combining of the parts can be donereliably and easily without the parts being misplaced.

Next, the partition 10 assembled tentatively as described above is pressfitted and combined in a liquid tank into and with the main metal member1, which is vulcanization bonded to the vibration isolating base member2 into a unitary body, as the air is discharged. During this time, theouter circumferential portion 26 of the partition plate member 16 ispress fitted firmly and liquid-tightly in the inner circumference of themain metal member 1 via the seal rubber layer 2 a up to the position inwhich the outer circumferential portion 26 engages the circumferentialedge portion 2 b of the main liquid chamber-side surface (lower surfacein the drawings) of the vibration isolating base member 2. After the airis extracted, the outer circumferential edge portion 27 of the partitionreceiving plate 17, a portion of the first diaphragm 4 including thereinforcing member 41, and the opened edge portion 51 of the secondmetal fixing member 5 are clamped together by swaging the lower endportion 1 a of the main metal member 1. A liquid entering thechange-over chamber 12 is discharged by taking out the same from theliquid tank. A rubber plug is inserted into the communication passage 21before the assembling of the vibration isolator so the change-overchamber 12 may be used by removing the rubber plug after the liquid istaken out from the liquid tank.

Accordingly, the switchably controlled liquid sealed type vibrationisolator A of FIG. 1 is assembled easily and is formed so that amovement of the second diaphragm 11 on the side of the second auxiliarychamber 9 can be switchably controlled to a moving condition and anon-moving condition by a switching regulating operation introducing anegative pressure and an atmospheric pressure into the change-overchamber 12, which is provided along with the main liquid chamber 7,first and second auxiliary liquid chambers 8, 9, first and secondorifices 13, 14, and first and second diaphragms 4, 11, and which isadjacent to the second auxiliary liquid chamber 9 joined to the secondorifice 11 of a lower liquid passage resistance.

In the vibration isolator thus assembled, the partition plate member 16which presses the second diaphragm 11 to form the second auxiliaryliquid chamber 9 and second orifice 14 is fitted firmly in an engagedstate around the outer circumference of the main partition member 15 bya swaging device for the same outer circumference. Therefore, the mainpartition member 15 and partition plate member 16 are combined togetherthus preventing their being separated from each other, and the seconddiaphragm 11 is retained in a pressed state reliably. Accordingly, evenwhen the fluctuation of the liquid pressure ascribed to the vibration ofthe vibration isolating base member 2, and permanent set in fatigue ofparts due to heat occur, there is not the possibility that thedeficiency of the sealability of parts and the short-circuiting oforifices occur.

When the partition plate member 16 is swaged to the main partitionmember 15 as mentioned above, the circumferential edge portion of thesecond diaphragm 11 can be held in a clamped state between theprojection 16 a and the main partition member 15. Therefore, as shownin, for example, FIG. 5, this vibration isolator can also be practicedby clamping the circumferential edge portion of the second diaphragm 11by the projection 16 a and main partition member 15 with the metalcollar 20 of the second diaphragm 11 omitted.

As described above, in the switchably controlled liquid sealed typevibration isolator according to the present invention, the innerpartition dividing the inner chamber into the main liquid chamber 7 andtwo auxiliary liquid chambers 8, 9, is formed so that the partition 10can be assembled initially in the air. This enables the pluralconstituent parts to be combined together reliably and easily withoutthe parts being mislocated. Furthermore, relative displacement of theconstituent parts in a vehicle-mounted state due to the variationthereof and the lapse of time is reduced, and the sealed condition ofthe parts is maintained in excellent condition, and contributes to theimprovement of the durability of the vibration isolator.

What is claimed is:
 1. A vibration isolator comprising: a fitting memberhaving a first portion for attachment to one of a vibrating body and asupport thereof and a second portion; an elastic base member having afirst side fixed to the second portion of the first fitting member and asecond side; a tubular member having a first end fixed to the secondside of the elastic base member and a second end; a partition device,disposed in the tubular member, having an outer diameter, a firstpartition side opposing the elastic base member defining a main liquidchamber therebetween, and a second partition side opposite said firstpartition side, said partition device defining an orifice communicatingwith the main liquid chamber; a partition receiving plate having adiameter greater than the outer diameter of the partition device andhaving the partition device mounted thereon, the partition receivingplate having an annular portion extending beyond the outer diameter ofthe partition device, the partition receiving plate having an openingcommunicating with the orifice; a diaphragm disposed opposing thepartition receiving plate and defining an auxiliary liquid chambercommunicated with the main liquid chamber via said orifice, saiddiaphragm including an annular reinforcing plate at a periphery thereof;another fitting member for attachment to the other one of the vibratingbody and the support thereof, the another fitting member being disposedopposing said diaphragm to define an air chamber; and said second end ofsaid tubular member being swaged to clamp said annular portion of thepartition receiving plate, said annular reinforcing plate of saiddiaphragm which lies therewith, and said another fitting member mutuallyfixed in place together.
 2. The vibration isolator of claim 1, where insaid partition device includes a recess at said second partition side,and said partition receiving plate includes a protrusion protrudingtowards said partition device, said protrusion press fitted into saidrecess whereby said partition device is fixed to said partitionreceiving plate.
 3. The vibration isolator of claim 2 further comprisingsaid another fitting member having a flange clamped together with saidannular portion of said partition receiving plate and said annularreinforcing plate of said diaphragm by said second end of the tubularmember.
 4. A vibration isolator comprising: a fitting member having afirst portion for attachment to one of a vibrating body and a supportthereof and a second portion; an elastic base member having a first sidefixed to the second portion of the first fitting member and a secondside; a tubular member having a first end fixed to the second side ofthe elastic base member and a second end; a partition device, disposedin the tubular member, having an outer diameter, a first partition sideopposing the elastic base member defining a main liquid chambertherebetween, and a second partition side opposite said first partitionside, said partition device defining an orifice communicating with themain liquid chamber; said partition device including a main partitionmember and a partition plate, said partition plate forming the firstpartition side, defining an opening for the orifice to communicate withthe main liquid chamber, and having side portions fixed to a peripheralside of the main partition member and contacting an innercircumferential surface of the tubular member to seal the main liquidchamber with the exception of the orifice; a diaphragm disposed opposingthe second partition side and defining an auxiliary liquid chambercommunicated with the main liquid chamber via said orifice, saiddiaphragm including an annular reinforcing plate at a periphery thereof;another fitting member for attachment to the other one of the vibratingbody and the support thereof, the another fitting member being disposedopposing said diaphragm to define an air chamber; and said second end ofsaid tubular member being swaged to clamp said annular reinforcing plateof said diaphragm, and said another fitting member so that they aremutually fixed in place together.
 5. The vibration isolator of claim 4,wherein: said main partition member having a recess at said secondpartition side; said partition plate having a diameter greater than theouter diameter of the main partition member and having the mainpartition member mounted thereon; and said partition plate includes aprotrusion protruding towards said main partition member, and saidprotrusion is press fitted into said recess whereby said main partitionmember is fixed to said partition plate.